Last week, he rocked audiences with his cameo as a profane, hip-jiggling, Machiavellian movie chief in " Tropic Thunder." The role was designed to show the world -- and Hollywood insiders -- that the one-time king of Hollywood didn't take himself too seriously and even had comedic chops.

His performance was funny, but somehow as with all things Cruise these days, a black cloud emerged from the silver lining. His tour de force was overshadowed by yet another hellish publicity week, which included debates over whether "Tropic Thunder" was degrading to the mentally disabled as well as an inaccurate story that Sony had replaced Cruise in the film "Edwin A. Salt" with "it" girl Angelina Jolie. (According to several sources close to the project, it was Cruise who refused to commit to a start date, and his actual next film looks to be "The Tourist," a remake of the French thriller "Anthony Zimmer," to be directed by Lasse Hallström.)

On a more serious front, Cruise is facing the biggest crisis of his side career as a studio mogul with the departure -- also announced last week -- of Paula Wagner as chief executive of United Artists, the mini-studio the pair co-own with MGM. Almost two years ago, Cruise and Wagner had triumphantly taken over the studio with ambitious plans to bring it back to its roots as an artist-run haven. MGM honcho Harry Sloan was able to negotiate a $500-million film fund for the pair from Merrill Lynch, which required them to release four films a year for five years with budgets between $40 million to $50 million. Yet Wagner's inability to greenlight pictures was threatening to jeopardize the Merrill Lynch money. So far, UA had put out only one film, "Lions for Lambs," which earned $15 million and appears to be the biggest domestic box office bust of Cruise's storied career. (Wagner declined to comment for this article.)

Still, the departure of Wagner had to be a blow. Wagner has worked with the actor for more than 25 years, first as his agent and later as his business partner. And yet, on some level, Cruise acquiesced to her ouster, as the situation between Wagner and their cohorts at MGM had become untenable.

Three years after his meltdown in which he bizarrely jumped on Oprah Winfrey's couch, and proselytized about Scientology, Cruise remains at a career crossroads. He's still a major international star but somehow perennially dodging ill will and innuendo in the media circles of New York and Los Angeles. As an actor, he's attractive to studios but no longer at the top of the Hollywood food chain.

But in an era when money for Hollywood projects is drying up, Cruise personally has access to a vault of cash to make movies. Those close to Cruise say the actor has no desire to change his role at UA -- and now, he's the one there who can greenlight films , with budgets up to $60 million. Cruise declined to be interviewed , though Sloan issued a statement that Cruise intended to stay as a "full partner in control of UA." Unlike Viacom head Sumner Redstone, who unceremoniously tossed Cruise and Wagner off the Paramount lot in 2006, Sloan has been careful to state Cruise "is in the middle of one of the greatest careers our industry has ever seen."

Part of Sloan's deference to Cruise might come from the fact that the Merrill Lynch credit facility is in some way dependent on Cruise's ongoing participation at UA, said two well-placed sources.

Cruise's personal publicist Julie Polkes denied rumors that the Merrill Lynch credit line might be evaporating. "The UA funding is not at risk," she said. "It is 100% intact." MGM spokesman Jeff Pryor added, "United Artists will continue to make the films under the credit facility, and there's not going to be any changes." A Merrill spokesman did not return calls.

So much now rides on the success of Cruise's next film, " Valkyrie," for both Cruise the actor and Cruise the studio owner. Directed by Bryan Singer, the film is the true-life tale of a German military officer leading a plot to kill Hitler. The film has swirled in bad buzz, and the release date jumped around the calendar.

Last week, however, MGM announced it was releasing the film on Dec. 26, smack in Oscar season, after what UA marketing chief Mike Vollman said was a stellar test screening in Nevada. Another incentive to move the film's date might be the financial perks associated with releasing "Valkyrie" under MGM's rich cable distribution deal with Showtime, which is due to expire at the end of the year.

Undeniably, Cruise's next choice of film is an important one, and "The Tourist" is a tony thriller about an international money launderer, his girlfriend and a man she asks to pose as her husband. The final decision caps months of innuendo and discussion about Cruise's plans. In addition to "Edwin A. Salt," Cruise also worked on developing "The 28th Amendment," a Warners project that stalled, said an executive there, when the studio and Cruise disagreed on which of the two leads the actor should play -- and director Phil Noyce bailed to make "Edwin A. Salt." Meanwhile, according to a Paramount executive, talk of a sequel to "Top Gun" or another "Mission Impossible" is just hoopla.

According to the executive, the studio did discuss internally making a new installment of Cruise's signature franchise, "Mission Impossible," without Cruise but backed off once it realized the extent of his contractual rights over the material, both as a producer and star.

Five years ago, it would have been unthinkable that a studio wouldn't jump at making another installment of a Cruise franchise, but he faces the reality of any actor moving into middle age. It's unclear whether he's going to reclaim his popularity or, as his "Tropic Thunder" character says in the movie, become "a white star heading toward a black hole."

"Tom's the last guy I worry about," said publicist Howard Bragman. "He did the catharsis interview on 'Oprah' [this past May], which was the smart thing to do and put all that behind him. He has thick skin. You don't get to be his age and his success level without taking some hits, without having some purple hearts."

While John Travolta had Quentin Tarantino to help make him hip again, Cruise has Ben Stiller for now. The two are still developing the comedy "The Hardy Men" with director Shawn Levy, about what happens when the Hardy boys -- the beloved detective brothers from the book series -- grow up. Stiller, who directed and co-wrote "Tropic Thunder," declined to be interviewed, though he e-mailed a quote about Cruise, noting that "he has always been willing to take chances in his career, and what he did in the movie was amazing to me. He has a great sense of humor and his work elevated the picture."